题目内容
(15分)一质量
的小物块以一定的初速度冲上一足够长的斜面,斜面的倾角
.某同学利用传感器测出了小物块从一开始冲上斜面上滑过程中多个时刻的瞬时速度,并用计算机作出了小物块上滑过程的速度—时间图线,如图所示.(已知重力加速度
,
,
)求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250042380285256.jpg)
(1)小物块冲上斜面过程中加速度的大小
;
(2)小物块与斜面间的动摩擦因数
;
(3)小物块沿斜面上滑的过程中克服摩擦阻力做的功
.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004237950634.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004237965478.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004237981666.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004237996649.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238012655.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250042380285256.jpg)
(1)小物块冲上斜面过程中加速度的大小
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238043283.png)
(2)小物块与斜面间的动摩擦因数
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238059301.png)
(3)小物块沿斜面上滑的过程中克服摩擦阻力做的功
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238293396.png)
(1)
(2)
(3)![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238355567.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238308631.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238324526.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238355567.png)
试题分析:(1)由小物块上滑过程的速度-时间图线,可得小物块冲上斜面过程中加速度的大小为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250042383711259.png)
即加速度大小为8m/s2.
(2)对小物块进行受力分析如图所示:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250042383863301.png)
有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238402779.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238433780.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238449528.png)
代入数据解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238324526.png)
(3)速度-时间图象中面积表示位移得小物块沿斜面滑行距离为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238620822.png)
则小物块沿斜面上滑的过程中克服摩擦阻力做的功
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250042386361002.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004238667352.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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